[zbentley]

Some of those already exist, e.g. https://bellard.org/tcc/

However, they're not in widespread use. I would be curious to learn if there's any data/non-anecdotal information as to why. Is it momentum/inertia of GCC/LLVM/MSVC? Are alternative compilers incomplete and can't actually compile a lot of practical programs (belying the "relatively simple program") claim? Or is the performance differential due to optimizations really so significant that ordinary programs like e.g. vim or libjpeg or VLC or whatnot have significant degradations when built on an alternative compiler?